Blinking Overdrive Light

[ValerieE]

Hello,

I have a 1998 Ford Expedition and just last week the overdrive light has begun to start flashing at any given time. Any suggestions on the possible problem?

Valerie

[way2old]

You need to have the code read. Yhey should store in the PCM so any scanner capable of reading OBDII codes will pull them. Post back with the code numbers and we can help you.

[pennypicher]

I'll becurious too as my Aerostar has been doing this for years off and on. Sometimes it wont come on for months.

[OxfordDawg]

Only thing about the flashing OD light is that no one can read the codes with a regular OBII scanner. Mine started a couple of months ago and the tranny shop said it was a solenoid, so they replaced the pressure control solenoid. About three weeks later it started up again. Replaced the PWM and PCS (in my garage) and had the old ones checked and they were both within spec. Don't trust my tranny guy and he's the only one besides the Ford dealer in town - where they really don't even want to see you if you didn't buy from them.

Other than the flashing light and the ensuing pressure ramping, it shifts great. Any other thoughts?

[ModMech]

Originally Posted by OxfordDawg

Only thing about the flashing OD light is that no one can read the codes with a regular OBII scanner.

Hmm, I have never had any problems reading transmission codes with any of the three code readers I own.

Mine started a couple of months ago and the tranny shop said it was a solenoid, so they replaced the pressure control solenoid. About three weeks later it started up again. Replaced the PWM and PCS (in my garage) and had the old ones checked and they were both within spec. Don't trust my tranny guy and he's the only one besides the Ford dealer in town - where they really don't even want to see you if you didn't buy from them.

Other than the flashing light and the ensuing pressure ramping, it shifts great. Any other thoughts?

A flashing OD light is MOST often caused by high ATF temperatures, ad the second most common cause is excessive TC clutch slippage (which incidentally will casue high ATF temps).

[Allbert]

Originally Posted by ModMech

Hmm, I have never had any problems reading transmission codes with any of the three code readers I own.



A flashing OD light is MOST often caused by high ATF temperatures, ad the second most common cause is excessive TC clutch slippage (which incidentally will casue high ATF temps).

I know OxfordDawg and helped him with the solenoid swaps he mentioned... I think we used a CarChip to try to retrieve any trouble codes that might have been stored when the O/D light started flashing, but nothing came up. The blinking has stopped since he posted this, but it was strange because it actually came on after about 2 minutes on our test drive after replacing the hardware, so the fluid was way below normal operating temp. I was thinking there might be an issue with the temperature sensor, but we haven't checked that circuit since the flashing light issue went away on its own.